Vitamin E is a fat-soluble vitamin that is absorbed only with long chain fatty acids. A defect in either the absorption or digestion of lipid can therefore lead to deficiencies in this and other vitamins, due to their binding with unabsorbed fatty acids (Simpson, K W and Michel, K E. Micronutrient status in patients with gastrointestinal disease. Proceedings ACVIM, Denver, Colo., pp. 651-653, 2001). Hence, a pet with low lipid digestibility is susceptible to several potential nutritional deficiencies, which can compromise its health.
Studies on senior cat nutrition have shown that a significant number of older pets—such as those above the age of 9 years—exhibit a decreased capacity to digest fat. Several scientific publications have likewise reported an age-related decrease in lipid digestibility in cats (Burkholder. W J. Age-related changes to nutritional requirements and digestive function in adult dogs and cats. JAVMA, Vol 215, No. 5, Sep. 1, 1999; Nicholson A, Watson A D J. Mercer J R. Fat malassimilation in three cats. Australian Veterinary Journal, Vol. 66, No. 4, April, 1989; Peachey S E, Dawson J M, Harper E J. The effects of aging on nutrient digestibility by cats fed beef tallow, sunflower oil or olive oil enriched diets).
There can be any of a number of pathologies that can lead to poor digestibility of lipids. Malabsorption and maldigestion can occur from almost any diffuse disease of the intestine, from exocrine pancreatic insufficiency or from unknown causes. In the case of cats, pancreatitis occurs at a prevalence rate of about 0.15% to 3.5% and may account for some cases of poor fat digestibility. Diffuse intestinal diseases, such as intestinal lymphoma, small intestinal bacterial overgrowth, inflammatory bowel disease and liver disease, may also lead to reduced nutrient absorption in the small intestine.
Cases of pancreatic insufficiency are sometimes treated in veterinary practice by the addition of raw pancreas to the diet of the animal. The pancreas should not be heated to avoid denaturation of digestive enzymes. This kind of procedure is not convenient for the pet owner to have to perform on a regular basis. Commercially made enzyme supplements, for example as sold under the trade name Viokase V (believed to be a trade mark of Axcan Pharma US, Inc. of Birmingham, Ala.), are effective in improving fat digestibility in animals affected by pancreatic insufficiency, but they are expensive when given in the requisite amounts. They are therefore unsuitable for inclusion in the regular diet of a pet.
Nicholson et al (op. Cit.) disclosed that dietary pancreatic extract supplementation of cats presenting with poor fat digestibility almost doubled fat digestibility, although enzyme supplementation failed to increase fat digestibility to normal levels in all three cats tested. These findings point to pancreatic enzyme supplementation being able to achieve a partial correction.
Suzuki et al (Suzuki A, Mizumoto A. Rerknimitr R. Sarr M G, Dimagno E P. Effect of Bacterial or Porcine Lipase with Low- or High-Fat Diets on Nutrient Absorption in Pancreatic-Insufficient Dogs. Gastroenterology 1999; 116:431-437 The American Gastroenterological Association) studied the effects of bacterial lipase, porcine lipase and diets on protein absorption (inter alia) in pancreatic-insufficient dogs. They concluded that high-fat and high-protein diets optimize fat absorption with both enzymes and proposed to study the effects in humans.
International patent publication WO01/62280 discloses compositions that include crosslinked lipase crystals that are highly resistant to proteolysis and acid degradation. It recognizes that fat-soluble vitamin deficiency, for example vitamin E, is but one of the commonly observed consequences of fat malabsorption.
The prior art does not address the problem of vitamin E deficiency in a dietary framework. Nor does it suggest a dietary solution for prevention of vitamin E deficiency or conditions related to it.
For purposes of this specification, the term lipid fraction should be understood to mean a group of compounds that are insoluble in water, the group embracing fats, oils, waxes, phosphatides, cerebrosides, sterol, terpenes and the like, most of these including a fatty acid in their structures. Lipids can function to carry or transport a nutrient from a food source to the intestine and to the site of utilization, such as in a cell of the recipient's body.
“Digestion”, as used in this specification, means the process of breaking down a complex food matrix into its constituent parts, for example fats to glycerol and fatty acids. The breaking down process is primarily by action of gastric, hepatic and pancreatic enzymes.
“Absorption” as used in this specification, means the passage of the products of the breaking down process across the intestinal wall into the blood stream.
“Digestibility”, as used in this specification, means the quantity, expressed in percentage form, of a nutrient that is digested and absorbed in relation to the total nutrient quantity ingested by the animal.
“Assimilation”, as used in this specification, means the process of incorporation of simple molecules, produced from food digestion and absorbed into the body, into the complex compounds forming the constituents of the organism.
It is thus an object of the invention to provide a nutritional product that, when administered to a pet having sub-optimal serum levels of vitamin E, improves the digestibility of lipid and lipid-linked compounds, enabling more effective absorption or assimilation of vitamin E. Another object is to provide the pet and pet owner with advantages associated with effective assimilation of vitamin E.
A further object is to provide a complete pet food or supplement for a complete pet food that provides dietary means to aid a pet animal to absorb vitamin E.
Another object of the invention is to provide a method of improving vitamin E absorption in a pet animal, especially a senior pet.
A further object is to provide a means of improving the transportation of vitamin E into the a pet's tissues.